R
aw sewage produced
by millions of Londoners
once poured into the
Thames River for decades, until
the stench of the effluent became
so bad that in 1858 action was
demanded. When a new system
of sewers, pumping stations, and
treatment works revolutionized the
city’s sanitation, deaths and illness
from cholera and other bacterial
infections fell dramatically, and
the river became much cleaner.
Human activity has always
altered the environment, but its
impact increased dramatically
in the mid-18th century with the
Industrial Revolution that began in
Britain, and spread to Europe, North
America, and beyond. The negative
effects can be broadly divided
into pollution, and destruction
of resources and habitats.Scottish-American environmentalist
John Muir was one of the first to
identify habitat degradation and
destruction as problems, and in
1890 he won protection for the
Yosemite Valley in California.
However, despite a steady increase
in protected natural environments,
in the 20th century, the destructive
pressures of human development
have grown ever more powerful.Trees and climate change
Forest has been especially hard-hit,
mainly due to the dual demands
of lumber required for construction
and fuel, and land cleared for
agriculture and development.
An estimated 54,000 sq miles
(140,000 sq km) of tropical rain
forest—which contains the greatest
biodiversity—is cleared each year.
Scientists will never know howmany forest-dwelling species died
out before they were “discovered.”
Deforestation also contributes
to global climate change. As trees
photosynthesize, they absorb
carbon dioxide and release oxygen.
However, less forest means that
more CO 2 stays in the atmosphere,
fueling the greenhouse effect and
global warming.
Carbon and other greenhouse
gases are emitted from cars and
factories burning fossil fuels. Since
1958, American scientist Charles
Keeling’s measurements of
atmospheric CO 2 have shown that
CO 2 emissions are increasing at
an ever-faster rate. While a minority
of scientists maintain that human
activity is not responsible, climate
change has warmed the continents.
The consequences, including trees
coming into leaf and flowersINTRODUCTION
1858
During the Industrial
Revolution, London’s
“Great Stink”
prompts legislation
to curb air and
water pollution.1872
The world’s first
national park is
created in the US
at Yellowstone
to preserve its
natural habitat.1958
Charles Keeling
starts to record the
year-on-year rise
in atmospheric
carbon dioxide
levels.1963
Gene Likens begins
work to establish
the relationship
between water
quality and
life forms.1987
Chico Mendes
lobbies the US
Congress to stop
funding projects
that damage the
Amazon rain forest.1859
Rabbits are released
in Australia; their
population explosion
results in chaos for the
environment.1955
The term “urban
sprawl” is used for
the first time, by The
Times newspaper in
the UK.1962
Rachel Carson’s
book Silent Spring
exposes the harmful
effects of pesticides
on the environment.1979
The One Child
Policy is initiated
in China to
control the rapid
population growth.228
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